It is well known in the multiple speed ratio transmission art that synchronizer mechanisms may be used to reduce shift time of all or some of the transmission gear ratios. It is also known that the shift effort required by a vehicle operator, i.e., force applied to a shift lever, may be reduced by use of synchronizer mechanisms of the self-energizing type. Since operator shift effort generally increases with vehicle size, synchronizer mechanisms of the self-energizing type are especially important for heavy duty trucks. Prior art examples of synchronizers that are relevant to the synchronizer herein may be seen by reference to U.S. Pat. Nos. 5,078,244; 5,092,439 and 5,339,936 which are incorporated herein by reference.